An organic light-emitting device includes a thin film which contains a fluorescent organic compound and which is arranged between an anode and a cathode. The injection of electrons and holes from the respective electrodes produces excitons of the fluorescent organic compound. Light emitted when the excitons return to the ground state is used.
Among organic light-emitting devices, in particular, organic light-emitting devices using electroluminescence are sometimes referred to as organic electroluminescent devices or organic EL devices.
The characteristic features of organic light-emitting devices include high luminance at a low applied voltage. Furthermore, the use of organic light-emitting devices enables us to produce rapid-response, thin, lightweight light-emitting apparatuses that emit light beams with a variety of emission wavelengths. So, organic light-emitting devices will be used for a wide variety of applications.
For the reasons, novel compounds, which are important in the production of high-performance organic light-emitting devices, have been intensively developed.
For example, PTL 1 describes a benzo[k]fluoranthene derivative serving as a compound used in a light-emitting layer.
There is still room for improvement in the organic compound described in PTL 1 and organic light-emitting devices including the compound from the viewpoint of achieving practical use. Specifically, organic light-emitting devices are required to have a higher-intensity optical output or higher photoconversion efficiency. Furthermore, it is necessary to minimize the variation with time by prolonged use and to improve durability, for example, the resistance to degradation due to oxygen, humidity, and so forth.
When application of organic light-emitting devices to image display apparatuses, such as full-color displays, is contemplated, it is necessary for organic light-emitting devices to have satisfactory color purity and emit blue light with high efficiency. However, these problems are not fully solved.
Accordingly, an organic light-emitting device having high color purity, luminous efficiency, and durability and a novel compound used to produce the device have been demanded.